| 摘要 |
PURPOSE:To read out exactly a data by comparing a reference line detecting output with a position detecting circuit output and detecting whether the read- out position of a read data is within an allowable range or not. CONSTITUTION:In a reference line detecting device 50, a signal having level corresponding to the optical quality of a reference line among output signals from a read sensor 10 is fetched by a signal level discriminating circuit 51, the duration time of its signal is measured 52 and when its time reaches a reference value, a reference line detecting signal is outputted from a deciding circuit 53. Also, in a discriminating device 60, a position in the visual field of the sensor 10 is detected by a read-out position detecting circuit 61 and a range where the existence of the reference line is allowed is set in advance by using an allowable range setting circuit 62. In this state, whether the read-out position of an output data from the sensor 10 is within the allowable range or not is read out, compared 63 with the output of the position detecting circuit 61 and decided 60. In this way, by using the sensor 10 for detecting a position shift, an inclination, etc., an input signal is made to follow exactly a data train on data recording area.
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